back to atomic theory

Lesson activities

Activity 1
In pairs/threes complete the activity below, "Atoms and their isotopes". Only move on to the activity 2 when both of you (or all three of you) have finished the tasks and are satisfied that you have met the success criteria described on the sheet.



Activity 2
Below in blue are the assessment statements from the IB chemistry subject guide for topic 2 section 2.1. Which of the 6 statements have ideas which you have read about in the activity 1?
In your class book, draw a concept map that links all ideas that are described in the 6 statements below. Once you are both ready, show your map to each other and through discussion complete your own map if necessary.

2.1.1 State the position of protons, neutrons and electrons in the atom.
2.1.2 State the relative masses and relative charges of protons, neutrons and electrons.
2.1.3 Define the terms mass number (A), atomic number (Z) and isotopes of an element
2.1.4 Deduce the symbol for an isotope given its mass number and atomic number.
2.1.5 Calculate the number of protons, neutrons and electrons in atoms and ions from the mass number, atomic number and charge.
2.1.6 Compare the properties of the isotopes of an element.

Activity 3
Research task on radioisotopes - use the internet.
Some isotopes are radioactive and are called radioisotopes. Such isotopes are dangerous. However, despite their dangers some radioisotopes are useful to us.


Within your group
  • Each member chooses a different isotope and completes the research task.
  • Once the research task has been completed each member explains their poster to the others in the group.

Activity 4
Research task on the mass spectrometer:
The mass spectrometer is an important tool in chemistry. On a piece of A3 paper complete the following tasks as a group
  • When was the first mass spectrometer made and by who?
  • Find out what chemistry knowledge and understanding the mass spectrometer has allowed us to obtain.
  • Sketch a mass spectrometer, identify the 5 main parts and explain why each part is necessary. You can use this animation to help you although it is noisy: http://www.colby.edu/chemistry/OChem/DEMOS/MassSpec.html
  • Find an example of a mass spectrogram for an element and explain how it is used to find the relative atomic mass of that element.
  • Nominate 1 person who will go to another group and explain to them the findings of your research.

Activity 5
Handout topic 2:
  • Complete the table on page 2.
  • Study the example on page 5 showing you how to calculate the relative atomic mass of an element using the different isotopes of the element and the abundance of each isotope.
  • Complete the exercises on page 5.

Activity 6
Do the flame test investigation and record your observations in your log book.


Activity 7
Within your groups, complete the task below, "Analysis of spectral lines". Before you start the task you need to have an understanding of the following:
  • the Bohr model of an atom: in your work book draw a Bohr model of a magnesium atom.
  • the electromagnetic spectrum: identify how the different waves are similar and how they are different; you need to focus in particular on infrared, visible light and ultraviolet
.